This invention relates generally to milking machines, and more particularly to short milk tubes that provide a conduit between a milking claw and a teat cup liner or an automatic teat dip applicator.
Dairy hygiene is of paramount importance. Keeping cows and other milk producing animals clean and healthy minimizes contamination of milking equipment and the milk. Dairy producing animals such as cows have teats and udders that may be washed before milking to prevent dirt and debris from entering the milking system used to milk cows. In addition, application of antimicrobial teat dips before or after milking can reduce the incidence of mastitis in cows, thus keeping them healthy and producing uninfected milk.
Milking equipment is cleaned regularly to rinse debris and milk residue from the equipment, and to disinfect the equipment so that cows subsequently milked on the same equipment will not be subjected to undue exposure to potentially infectious conditions that can cause mastitis.
Keeping individual animals healthy is important because healthy animals produce more and better milk. Milk produced by cows in a dairy is transferred to a bulk storage tank. Infected milk from one cow can contaminate all of the milk in the bulk tank at considerable loss to the dairyman.
Applying teat dips pre- and post-milking, and back-flushing milking systems therefore are very important to dairy production. Nonetheless, the time and expense of performing these operations is considerable and a number of teat dip applicators have been developed to optimize the quantity of teat dip applied in a minimum amount of time.
One such system has been developed that is attached to the milking cluster and automatically applies a post-milking teat dip to cow teats before the milking cluster is detached from the cow. This system is disclosed in WO 99/66787 to Dietrich and sold by Westfalia-Surge, Inc. of Naperville, Ill. under the “Air Dip” brand name. It saves the time normally needed to hand apply teat dip after the milker unit is detached. By connecting such an applicator to a milking cluster there is added weight that can cause the teat cups to fall from the cow in a manner that damages the teat cups and makes flushing the system more difficult. Also, the load of the applicator can wear down or damage related equipment, particularly the flexible short milk tubes that transport milk away from the cow. In this type of applicator, the teat cup assembly must be back-flushed to rinse out the teat dip before the next cow is milked.
The conventional design of milking units requires connections to conduct air and milk from multiple teat cup assembly outlets to milking claw (manifold) inlets. Often this connection is integral with the teat cup liner fitted within the teat cup to provide an “inflation” that alternately squeezes and releases a teat to induce milking. The inflation responds to alternating vacuum from the dairy's central vacuum line.
In other designs, the connection between the teat cup assembly and the milking claw is made from a separate rubber tube, known as a short milk tube. A number of short milk tube designs are disclosed in U.S. Pat. Nos. 2,341,953; 3,079,891; 4,043,739; 4,090,471; 4,441,454; 4,745,881; 5,007,378; 5,482,004; and 5,572,947.
The requirements of a short milk tube include, providing a fluid-tight conduit for milk and air away from the teat cup assembly and to the milking claw, having and maintaining adequate cross-sectional area to ensure adequate milk flow rate, being flexible enough to allow different teat cup assemblies to adapt to different animals and changing udder size as milk is extracted, resisting damage from the edges of milking claw inlet nipples if the unit is dropped or kicked, and providing a positive connection to an automatic teat dip application valve.
Previously known short milk tubes do not provide the necessary control over the position of teat cup assemblies as they are being detached from cows.
Thus, there is a need for a milking unit that can be used with automatic teat dip applicators to prevent damage to the milking claw when detached from cows and to enable the system to be adequately back-flushed when necessary.